Question 1

Which of the following best explains why water is an effective solvent for ionic compounds in biological systems?

Accepted Answer

Water molecules are polar and can surround ions, stabilizing them through ion-dipole interactions.

Question 2

Which of the following statements about the hierarchy of biological organization is correct?

Accepted Answer

Cells are the basic unit of life and are organized into tissues, which form organs.

Question 3

A patient is experiencing acidosis due to a buildup of lactic acid. Which buffer system in the blood is primarily responsible for minimizing the pH change?

Accepted Answer

The bicarbonate buffer system

Question 4

Which of the following equations correctly represents the relationship between Gibbs Free Energy ($\Delta G$), enthalpy ($\Delta H$), entropy ($\Delta S$), and temperature ($T$)?

Accepted Answer

$\Delta G = \Delta H - T\Delta S$

Question 5

Which property of water is most important for maintaining temperature homeostasis in living organisms?

Accepted Answer

High specific heat capacity

Question 6

A solution contains 0.1 M acetic acid ($\mathrm{p}K_a = 4.76$) and 0.1 M sodium acetate. What is the pH of the solution? (Use the Henderson-Hasselbalch equation: $\mathrm{pH} = \mathrm{p}K_a + \log_{10}\left(\frac{[A^-]}{[HA]}\right)$)

Accepted Answer

pH = 4.76

Question 7

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids linked by peptide bonds

Question 8

Which of the following amino acids is most likely to be found on the surface of a soluble protein in an aqueous environment?

Accepted Answer

Glutamic acid

Question 9

A biochemist is separating a mixture of proteins using high-performance liquid chromatography (HPLC). Which property of the proteins is most likely being exploited in reverse-phase HPLC?

Accepted Answer

Hydrophobicity

Question 10

Which of the following statements about the standard free energy change ($\Delta G^\circ$) is correct?

Accepted Answer

$\Delta G^\circ$ is measured under standard conditions: 1 M concentration, 1 atm pressure, and 25^\circ$C$.

Question 11

Which of the following best explains why the peptide bond is planar?

Accepted Answer

The peptide bond has partial double-bond character due to resonance.

Question 12

Which of the following is a correct statement about the relationship between $\Delta G$ and the equilibrium constant $K_{eq}$?

Accepted Answer

$\Delta G = -RT \ln K_{eq}$

Question 13

Which of the following best describes the difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have a nucleus, while prokaryotic cells do not.

Question 14

A solution of glycine (pI = 6.0) is adjusted to pH 2.0. What is the predominant form of glycine at this pH?

Accepted Answer

Positively charged ion

Question 15

Which of the following is NOT a property of living systems?

Accepted Answer

Ability to exist in thermodynamic equilibrium with the environment

Question 16

Which of the following best describes the role of hydrogen bonds in the structure of DNA?

Accepted Answer

Hydrogen bonds stabilize the double helix by connecting complementary base pairs.

Question 17

Which of the following amino acids contains a side chain that can be ionized at physiological pH?

Accepted Answer

Lysine

Question 18

A protein is denatured by heat. Which level(s) of protein structure are most likely disrupted?

Accepted Answer

Secondary, tertiary, and quaternary structures

Question 19

Which of the following best explains why enzymes are highly specific for their substrates?

Accepted Answer

Enzymes have active sites with unique shapes and chemical environments that complement specific substrates.

Question 20

Which of the following statements about entropy ($\Delta S$) in biological systems is correct?

Accepted Answer

Entropy is a measure of the disorder or randomness in a system.

Biochemistry Exam 1 Review: Chapters 1-4 Study Guide

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